A plan nearly 20 years in the making will finally pay off when M. Night Shyamalan’s Glass hits theaters in January 2019.

The director on Wednesday confirmed the movie will complete the trilogy that includes Unbreakable and Split—two seemingly unrelated movies that have one very important element in common. If you have yet to see Split, you may be wondering how it ties in. Consider this your spoiler warning.

When audiences saw Split, it was presented as its own thing, separate from everything else Shyamalan had done before. That is, until the very end, when it was revealed the movie was set in the Unbreakable universe.

In the film, we see David Dunn (Bruce Willis), who played one of the main characters in Unbreakable, learn about Kevin Wendell Crumb’s (Jame McAvoy) The Horde, a collection of 23 distinct personalities, which ultimately culminates in a final personality known as The Beast.

Glass will bring the universe’s big players together for the first time, including Dunn, Crumb, Elijah Price/Mr. Glass (Samuel L. Jackson), and Casey Cooke (Anya Taylor-Joy).

Here’s the movie’s official synopsis:

Following the conclusion of SPLIT, GLASS finds Dunn pursuing Crumb’s superhuman figure of The Beast in a series of escalating encounters, while the shadowy presence of Price emerges as an orchestrator who holds secrets critical to both men.

What’s cool is Shyamalan had planned this as a trilogy all along, which is a pretty big secret to keep for nearly 20 years. He previously revealed Crumb was supposed to appear in Unbreakable, but the director just couldn’t make it work. So, Split was born, and now we’re getting a movie to conclude the story.